CVE-2025-26399 SolarWinds Web Help Desk: unsafe data loading
In plain words: The program unpacks saved data from outside without checking it is safe. Usually lets an attacker run code on the server.
Confirmed exploited by CISA on · US federal patch deadline Mar 12, 2026
What to do
- Install SolarWinds's security update for Web Help Desk. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
- Product
- SolarWinds Web Help Desk
- CISA description
- SolarWinds Web Help Desk contain a deserialization of untrusted data vulnerability in AjaxProxy that could allow an attacker to run commands on the host machine.
- Type of flaw
- Unsafe data loading (CWE-502)
- Confirmed exploited
- Mar 9, 2026 — known to be used in ransomware attacks
- US federal patch deadline
- Mar 12, 2026
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Answering about CVE-2025-26399 ·
Questions about CVE-2025-26399
Is CVE-2025-26399 being exploited?
Yes. CISA added CVE-2025-26399 to its Known Exploited Vulnerabilities catalog on Mar 9, 2026, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2025-26399?
Install SolarWinds's security update for Web Help Desk. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2025-26399?
Only if you use SolarWinds Web Help Desk. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.